Oral humectants

ABSTRACT

The invention provides a mouth wetting agent and a mouth wetting agent for false teeth including a safe and easily usable polymer composition and capable of relieving symptoms of dry mouth by maintaining the wetting properties of an oral cavity and the stability of false teeth. The mouth wetting agent of the invention includes a polymer composition containing a pharmaceutically acceptable water-soluble polymer, a pharmaceutically acceptable polyvalent alcohol and water and/or artificial saliva.

TECHNICAL FIELD

The present invention relates to a wetting preparation applied into anoral cavity and, more specifically, to a mouth wetting agent and a mouthwetting agent for false teeth capable of relieving symptoms of dry mouthand including a safe and easily usable polymer composition.

BACKGROUND ART

The wetting properties of an oral cavity are maintained with saliva, butare lost upon decrease in saliva for a certain cause, thus allowing theoral cavity to be in a dry state. When the oral cavity is kept in a drystate for a long time, there occur various symptoms and functionaldisorders called dry mouth. The cause of such dry mouth includes variousdiseases causing an organic change in salivary glands, salivary glanddiseases accompanying general diseases, destruction of salivary glandcells by radiation treatment, HIV infection, a reduction in secretoryfunctions by aging, influence of various medicines administered, andmental fatigue and disorder caused by complicated social livingconditions. In persons of advanced age, dry mouth is a symptom observeddaily, which is considered attributable to a degenerative change insalivary glands with aging.

Insufficient secretion of saliva also adversely affects a full set offalse teeth, to cause problems such as deterioration in adsorption offalse teeth. Usually, a thin membrane of saliva is present between falseteeth and the mucous membrane of the oral cavity, to keep the oralcavity in a negative-pressure condition thus maintaining false teeth,and also serves as lubricating oil between the oral cavity and falseteeth. Even if well-fitted false teeth are used, the false teeth arepoor in adsorption where the mucous membrane is in a dry state, toproduce pain or bedsores in some cases upon rubbing the false teeth withthe mucous membrane.

Occurrence of dry mouth causes a large number of serious pains in dailylife, including not only dry feel in the oral cavity but also burningfeel in the mouth, sharp pain, tongue pain, taste abnormalities,inflammation of the mucous membrane in the oral cavity, ulcer formation,clefts in the tongue and in the edge of mouth, difficulties in chewing,swallowing and speaking, and there is strong demand for suitablemeasures to deal therewith.

In methods of treating or relieving these symptoms at present,artificial saliva and mouthwash are used, but merely bring abouttransient wetting in the oral cavity. Barotin, Cephalantin and variouskinds of herb medicines have been tried, but undesirable side effectsare recognized and sufficient effects cannot be obtained. Thus,therapeutic methods therefor are still not established.

On one hand, there are a wide variety of commercial false-toothstabilizers for the purpose of fixing and stabilizing false teeth, andas the commercial false-tooth stabilizers, gum-like hydrophobicsynthetic polymers such as vinyl acetate resin are mainly used. They areintended for use in stabilizing false teeth for a long time in the oralcavity, and thus they are water-insoluble and cannot be expected toexhibit wetting properties, and there is worry about safety because ofpossible elution of a plasticizer. Highly safe naturally occurringwater-soluble substances have also been studied, but they arehydrophilic polymers to be rendered heterogeneous with delayedabsorption of a very small amount of water thus feeling uncomfortableupon use, and after use, their washing is troublesome due tosolidification. For these disadvantages, these substances are rarelyused at present.

An object of the present invention is to provide a mouth wetting agentand a mouth wetting agent for false teeth, including a safe and easilyusable polymer composition and capable of relieving the symptoms of drymouth by maintaining the wet state of the oral cavity and the stabilityof false teeth, to solve the disadvantages in the conventional art.

DISCLOSURE OF THE INVENTION

As a result of intensive studies for achieving the above object, thepresent inventors found that a polymer composition containing a specificwater-soluble polymer, a polyvalent alcohol and water and/or artificialsaliva can serve as a mouth wetting agent and a mouth wetting agent forfalse teeth to exhibit an effect adapted to the object of the presentinvention; thus, the present invention has completed.

That is, the mouth wetting agent of the present invention includes apolymer composition containing a pharmaceutically acceptablewater-soluble polymer, a pharmaceutically acceptable polyvalent alcoholand water and/or artificial saliva.

According to the mouth wetting agent, the wetting feel in the oralcavity can be maintained for a predetermined time, thus relievingsymptoms accompanying dry mouth.

Preferable examples of the water-soluble polymer include cellulose-basedpolymers such as methyl cellulose, carboxymethyl cellulose, sodiumcarboxymethyl cellulose and hydroxyethyl cellulose, and these may beused alone or as a mixture of two or more thereof.

Preferable examples of the polyvalent alcohol include glycerin,propylene glycol and sorbitol, and these may be used alone or as amixture of two or more thereof.

Among the above water-soluble polymers and polyvalent alcohols, acombination of sodium carboxymethyl cellulose and glycerin isparticularly preferably used.

The compounding ratio of the water-soluble polymer is preferably 3 to 20wt %, and the compounding ratio of the polyvalent alcohol is preferably1 to 60 wt %.

By applying the above oral wetting agent onto false teeth and fittingthe false teeth to the oral cavity, the false teeth can be stabilizedand, simultaneously, the wetting feel in the oral cavity can becontinued.

BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, the present invention will be described in detail.

The pharmaceutically acceptable water-soluble polymer used in carryingout the invention is not particularly limited insofar as it exhibits athickening action upon dissolution in water, or is swollen or gelledwith water to exhibit stickiness. Such water-soluble polymer includeswater-soluble polymers such as naturally occurring polymers, forexample, sodium alginate, gum arabic, agar, tragacanth gum, carrageenan,xanthan gum, gelatin, pullulan and dextran, semi-synthetic polymers suchas dextrin, methyl cellulose, carboxymethyl cellulose, sodiumcarboxymethyl cellulose and hydroxyethyl cellulose, and syntheticpolymers such as polyvinyl pyrrolidone, carboxyvinyl polymer, polyvinylalcohol and Macrogol, and the like, and these may be used alone or as amixture of two or more thereof. From the viewpoint of properties of theresulting composition, such as swelling, gelling performance,thixotropy, delayed dissolution in water and stickiness to the mucousmembrane of the oral cavity, cellulose-based water-soluble polymers arepreferable in the present invention, among which sodium carboxymethylcellulose having a degree of etherification in the range of 0.7 to 1.0is the most preferable.

The pharmaceutically acceptable polyvalent alcohol in the presentinvention includes glycerin, propylene glycol, sorbitol, polyethyleneglycol and the like, and these can be used alone or as a mixture of twoor more thereof. In the present invention, glycerin, propylene glycoland sorbitol are preferable in respect of the ability to conferflexibility on the water-soluble polymer and wetting performance in theoral cavity, among which glycerin is particularly preferable in respectof taste and safety.

The mouth wetting agent of the present invention is constituted as apolymer composition with delayed dissolution in water, comprising thewater-soluble polymer and the polyvalent alcohol as essentialingredients having water added thereto to thicken, swell or gel thecomposition to exhibit stickiness. The amount and ratio of theingredients incorporated into the polymer composition are generallyarbitrary, but from the viewpoint of suitably keeping the handleabilityof the mouth wetting agent, preferably the water-soluble polymer is inthe range of 3 to 25 wt % and the polyvalent alcohol is in the range of1 to 60 wt %, more preferably the water-soluble polymer is in the rangeof 5 to 20 wt % and the polyvalent alcohol is in the range of 1 to 60 wt%, and still more preferably the water-soluble polymer is in the rangeof 8 to 15 wt % and the polyvalent alcohol is in the range of 4 to 30 wt%.

To confer suitable flexibility on the polymer composition, thepolyvalent alcohol is compounded in a ratio of 50 to 200 parts by weightto 100 parts by weight of the water-soluble polymer.

As the solvent constituting the polymer composition of the presentinvention, water is usually used, but in respect of keeping the oralcavity in a more wet state to improve functions, a preparation havinginorganic salts such as potassium chloride, sodium chloride, calciumchloride, magnesium chloride and dipotassium phosphate added to water,that is, artificial saliva is preferably used as the solvent. That is,the vapor pressure of artificial saliva is lower than that of water, andthus the polymer composition containing the artificial saliva can retainwater sustainedly thus easily keeping the oral cavity in a wet state.

The mouth wetting agent of the present invention can contain not onlythe above constituent components as essential ingredients, but alsovarious chemicals within a pharmaceutically acceptable range such as apreservative, a coloring agent, a flavoring and a saliva secretionaccelerator, which can be provided in various forms such as sheet, tubeand tablet.

When the mouth wetting agent of the present invention is used, thewetting feel in the oral cavity can be achieved by its conferredfunction of sustainedly releasing water molecules retained in thepolymer composition. The function of sustainedly releasing watermolecules can be arbitrarily regulated by changing the compounding ratioof the water-soluble polymer, the polyvalent alcohol and water and/orartificial saliva constituting the polymer composition, and the durationof the wetting feel can be established in the range from a short time(about 1 hour) to a long time (10 hours or more).

The mouth wetting agent of the present invention can be used as a novelmouth wetting agent for false teeth by applying it in a suitable amountonto false teeth and then fitting the false teeth to the oral cavitythereby achieving not only stabilization of the false teeth but alsowetting feel in the oral cavity. The mouth wetting agent of the presentinvention, upon application to false teeth, can be used preferably as amouth wetting agent for false teeth with improvements in total usabilityby suitably changing the compounding ratio of the water-soluble polymer,polyvalent alcohol and solvent constituting the mouth wetting agentthereby conferring suitable flexibility on the mouth wetting agent andimproving the applicability thereof onto false teeth and the ability offalse teeth to be fitted to the oral cavity.

Hereinafter, the present invention will be described in more detail byway of examples; however, the present invention is not limited to theexamples.

EXAMPLES 1 TO 5 AND COMPARATIVE EXAMPLE 1

The respective components shown in Table 1 were heated, stirred, mixed,dissolved transparently and cooled to prepare a mouth wetting agent. Thecompounding amounts are expressed in wt %, and the whole of thecomposition is 100 wt %. The artificial saliva in the compoundingingredients was prepared from the following compositions. In acomparative example, a commercially available false-tooth stabilizermade of vinyl acetate resin was used. (Compositions of artificialsaliva) Sodium chloride  84.4 mg Potassium chloride 120.0 mg Calciumchloride  14.6 mg Magnesium chloride  5.2 mg Dipotassium phosphate  34.2mg Pure water the balance (amount to adjust total to 100 g)(Evaluation of preparation as oral cavity wetting agent for false teeth)

Each of the mouth wetting agents obtained in Examples 1 to 5 andComparative Example 1 was evaluated by a panel of 10 persons. That is,the prepared mouth wetting agent was applied onto the back of falseteeth to be fitted to the oral cavity, and evaluated for its usabilityon the basis of the following items and evaluation criteria.

Flexibility of Mouth Wetting Agent

◯: Suitably flexible.

Δ: Slightly rigid or slightly soft.

×: Too rigid (brittle) or too soft.

Applicability onto False Teeth

◯: Easily applied.

Δ: Slightly hardly applied.

×: Hardly applied.

Fittability of False Teeth

◯: Easily fitted.

Δ: Slightly hardly fitted.

×: Hardly fitted.

Duration of Stabilization of False Teeth

⊚: Stabilization of false teeth lasts for 10 hours or more.

◯: Stabilization of false teeth lasts for several hours.

Δ: Stabilization of false teeth lasts for 1 hour or more.

×: Stabilization of false teeth is within 1 hour.

Duration of Wetting Feel in Oral Cavity

⊚: The wetting feel in the oral cavity lasts for 10 hours or more.

◯: The wetting feel in the oral cavity lasts for several hours.

Δ: The wetting feel in the oral cavity lasts for 1 hour or more.

×: The wetting feel in the oral cavity is less than 1 hour.

The results are shown in Table 1. The evaluation results are expressedon average by a panel of 10 persons.

From Table 1, it was recognized that the mouth wetting agents inExamples 1 to 5 exhibit an excellent effect on duration of the wettingfeel in the oral cavity and on duration of the stability of false teeth.On the other hand, the mouth wetting agent in Comparative Example 1 wasevaluated to be equivalent to the agents in Examples 1 to 5 in respectof the duration of stabilization of false teeth, but the wetting feel inthe oral cavity was not recognized at all.

The mouth wetting agents used in Examples 1 and 2 had suitableflexibility, were easily applied onto false teeth, facilitated fittingof false teeth, and exhibited a lasting effect on wetting feel in theoral cavity and on stabilization of false teeth, and were thus evaluatedas mouth wetting agents excellent in total usability and handleability.

EXAMPLE 6

Whether symptoms accompanying dry mouth were relieved by applying eachof the mouth wetting agents in Examples 1 to 5 onto the oral cavity of apatient with dry mouth was examined by a panel. As a result, all of thefive mouth wetting agents were recognized to relieve the symptomsaccompanying dry mouth, and particularly the mouth wetting agent inExample 3 had a significant relieving effect on clefts in the tongue andin the edge of mouth, and also exhibited an excellent effect thatspeaking was not hindered. From the above results, it is considered thata lower compounding ratio of the water-soluble polymer and a highercompounding ratio of the polyvalent alcohol are effective for use of thepolymer composition of the present invention as a mouth wetting agent.

INDUSTRIAL APPLICABILITY

For a method of treating dry mouth or relieving its symptoms, the mouthwetting agent of the present invention, unlike conventional artificialsaliva or mouthwash exhibiting a transient effect, can be used as amouth wetting agent for false teeth, based on a polymer with delayeddissolution in water and compounded with specific components, byapplying it onto false teeth particularly in dry-mouth patients havingfalse teeth put in thereby maintaining the wetting properties of theoral cavity and the stability of the false teeth to relieve thesymptoms. TABLE 1 Comparative Components Example 1 Example 2 Example 3Example 4 Example 5 Example 1 Sodium carboxymethyl cellulose 10.0 15.0 3.0 25.0 15.0 *Commercial Conc. glycerin  5.0 10.0 20.0 10.0  2.0product Methyl p-oxybenzoate  0.1  0.1  0.1  0.1  0.1 made of vinyl Purewater Balance — — — — acetate resin Artificial salvia — Balance BalanceBalance Balance Evaluation of usability Flexibility of mouth ◯ ◯ Δ Δ Δ Δwetting agent Applicability of ◯ ◯ ◯ Δ ◯ Δ false teeth Fittability offalse ◯ ◯ ◯ Δ ◯ Δ teeth Duration of ◯ ⊚ Δ ⊚ ◯ ⊚ stabilization of falseteeth Duration of wetting ◯ ⊚ Δ ◯ Δ X feel in oral cavity

1. A mouth wetting agent comprising a polymer composition containing apharmaceutically acceptable water-soluble polymer, a pharmaceuticallyacceptable polyvalent alcohol and water and/or artificial saliva.
 2. Themouth wetting agent according to claim 1, wherein the water-solublepolymer is at least one kind selected from cellulose-based polymers suchas methyl cellulose, carboxymethyl cellulose, sodium carboxymethylcellulose and hydroxyethyl cellulose.
 3. The mouth wetting agentaccording to claim 1, wherein the polyvalent alcohol is at least onekind selected from the group consisting of glycerin, propylene glycoland sorbitol.
 4. The mouth wetting agent according to claim 1, whereinthe water-soluble polymer is sodium carboxymethyl cellulose, and thepolyvalent alcohol is glycerin.
 5. The mouth wetting agent according toclaim 1, wherein the compounding ratio of the water-soluble polymer isin the range of 3 to 25 wt %, and the compounding ratio of thepolyvalent alcohol is in the range of 1 to 60 wt %.
 6. A mouth wettingagent for false teeth comprising a polymer composition containing apharmaceutically acceptable water-soluble polymer, a pharmaceuticallyacceptable polyvalent alcohol and water and/or artificial saliva.
 7. Themouth wetting agent for false teeth according to claim 6, wherein thewater-soluble polymer is at least one kind selected from cellulose-basedpolymers such as methyl cellulose, carboxymethyl cellulose, sodiumcarboxymethyl cellulose and hydroxyethyl cellulose.
 8. The mouth wettingagent for false teeth according to claim 6, wherein the polyvalentalcohol is at least one kind selected from the group consisting ofglycerin, propylene glycol and sorbitol.
 9. The mouth wetting agent forfalse teeth according to claim 6, wherein the water-soluble polymer issodium carboxymethyl cellulose, and the polyvalent alcohol is glycerin.10. The mouth wetting agent for false teeth according to claim 6,wherein the compounding ratio of the water-soluble polymer is in therange of 3 to 25 wt %, and the compounding ratio of the polyvalentalcohol is in the range of 1 to 60 wt %.
 11. The mouth wetting agentaccording to claim 2, wherein the compounding ratio of the water-solublepolymer is in the range of 3 to 25 wt %, and the compounding ratio ofthe polyvalent alcohol is in the range of 1 to 60 wt %.
 12. The mouthwetting agent according to claim 3, wherein the compounding ratio of thewater-soluble polymer is in the range of 3 to 25 wt %, and thecompounding ratio of the polyvalent alcohol is in the range of 1 to 60wt %.
 13. The mouth wetting agent according to claim 4, wherein thecompounding ratio of the water-soluble polymer is in the range of 3 to25 wt %, and the compounding ratio of the polyvalent alcohol is in therange of 1 to 60 wt %.
 14. The mouth wetting agent for false teethaccording to claim 7, wherein the compounding ratio of the water-solublepolymer is in the range of 3 to 25 wt %, and the compounding ratio ofthe polyvalent alcohol is in the range of I to 60 wt %.
 15. The mouthwetting agent for false teeth according to claim 8, wherein thecompounding ratio of the water-soluble polymer is in the range of 3 to25 wt %, and the compounding ratio of the polyvalent alcohol is in therange of 1 to 60 wt %.
 16. The mouth wetting agent for false teethaccording to claim 9, wherein the compounding ratio of the water-solublepolymer is in the range of 3 to 25 wt %, and the compounding ratio ofthe polyvalent alcohol is in the range of 1 to 60 wt %.